It does sound like "golfer's elbow". (It got it's name because it is common in golfers. The incidence of tennis elbow (on outside of elbow area) to golfer's elbow in tennis players is about 3:1.) But of course it is not possible to make a diagnosis on the internet, so the best is to get checked out medically.
The first thing is to REST. If you love tennis, that is very hard to do, but just look back on several recent threads on golfer's elbow on these boards to see the nightmare it can turn into if you let the inflammation really take hold.
Icing the area can help to reduce the inflammation.
Now I see your moniker is dudewithbabolat, and your racquet is fairly stiff with a flex rating of 67, and you are playing with a full bed of copolymer string at high tension. These are exactly the characteristics of frame and string that placed you at high risk for golfer's elbow in the first place. If you want to get back to playing sooner and not suffer an immediate recurrence, the best thing would be to play with a racquet that has a flex rating in the low 60's (Dunlop, Volkl and ProKennex player's sticks come to mind, but check out the racquet section of TT) and to use softer strings (multifilament or natural gut). The more flexible frame will allow you to string at a lower tension and still keep the ball in, and lower string tension is better for you arm.
Plan on coming back slowly after the pain has gone away, keeping the hitting sessions short and no serving at first.
Will you be able to go back to your current set up? Maybe, maybe not. (Certainly for your health, the answer would be it would be better not to.) That set up transfers an awful lot of force to your arm, rather than the set ups above that will absorb more of the force as you bash the ball. If you really want to get back to your frame/string then get forearms like Rafa. That is, the stronger the forearm muscles, the better your arm will be able to absorb the shock. Thus after your elbow area is better, begin to build up the forearm with dumbell wrist curls/reverse curls/rotations. And you can get a hand gripper device and Thera-band Flexbar blue or green pretty cheap on-line.
Good luck!
